What other sites (not necessarily tech) that use a badge/reputation system like stackoverflow. I am building a basketball website and will probably be looking for a metaphor thats more fitting than badges.

www.kongregate.com (flash gaming site) uses a very similar badge/achievement/points/reputation system. Check it out for ideas. You get points and badges for achieving various goals in many of the games. Although, I'm not sure you get anything for the points (abilities on the site, etc.) for the points. You just kinda get bragging rights. Also a lot of fun for when you're bored at work!

Jeff was inspired by the xbox system, so you may want to look at that. I'm not a gamer, but I guess you earn things for doing non-essential stuff in the game. This teaches you how to play the game, and encourages you to explore.